Gunfire cutoff device



UCL 26, 1954 P E- PLUESS '2,692,534

GUNF'IRE CUTOFF DEVICE Filed March 6,' 1952 INVENTOR TTORN EY P//z/L E. PL 055.5

BY v WW V Patented Oct. 26, 1954 GUNFIRE CUTOFF DEVICE Paul E. Pluess, Roslyn, N. Y., assigner to The Sperry Corporation, a corporation of Delaware 9 Claims. 1

This invention relates to circuit making and breaking systems and particularly to such systems when applied as gunfire cutoff or dead area control devices for ordnance equipment.

In the field of gunnery, it is common practice in designing certain types of guns to provide a re cutoff device whereby the firing circuit of the gun is broken during such time that the gun is aimed in a direction in which it is not desired to fire. Such devices are usually employed on rapid firing guns of the type that are traversed during ring. These installations are common on board ship and on aircraft where the field of re of a gun includes structure on the ship or aircraft. The usual procedure in such cases is to provide a fixed cam, properly oriented with respect to the structure to be protected, that is effective to control an electrical circuit or a mechanical linkage to prevent the operation of the firing circuit during the portion of the travel of the gun in which it bears on the friendly structure. Similar devices are also used on permanent anti-aircraft installations where it is essential to protect adjacent buildings.

Ordinarily, there is no need to provide a cutoff device for conventional field artillery because it is usually aimed in the direction of unfriendly territory and, as .a rule, has a limited field of lire. However, in recent years improvements in mobile ordnance equipment have created a different situation. The increased use of heavy probing attacks and large flanking movements require that the attacking force be almost completely dependent on its own artillery. Since the forces are subject to severe interdiction attacks by enemy aircraft, it is essential that they have artillery that can be used with equal facility for anti-aircraft activity as well as for the support of ground troops.

For such situations, special purpose guns have been developed. These guns must be of heavy caliber to be effective against modern aircraft, and must have a field of fire that includes a complete circle in azimuth and from the zenith to below the horizon in elevation. However, because of the large caliber and long range of these guns, every effort must be made to prevent inadvertent fire from being directed at supporting troops, supply lines, and friendly rear areas. When engaging enemy aircraft, it is impossible for a battery commander properly to direct his fire and, at the same time, keep in mind the location of friendly deployments. Therefore, it is essential that such guns be provided with fire cutoff devices that can readily be made operable 'azimuth and elevation position.

automatically to prevent ring in any dead area, i. e., one occupied by friendly troops or installations.

Although the firing cutoff devices presently in use are suitable for applications in which the dead areas remain fixed relative to the gun, they are not suitable for the situations described above. Under these conditions it is essential that the cutoff device be such that it can be rendered effective to safeguard surrounding dead areas immediately after the gun is brought to a new firing location. In addition, it must be sufficiently flexible that the effective field of fire can be changed at will and on extremely short notice in order that the gun be adaptable to rapidly changing tactical conditions.

As a solution to this problem, the present invention provides a system whereby at any given gun location the surrounding dead area may quickly be represented as a two-dimensional pattern and the firing of the gun may automatically be controlled from this pattern in accordance with its To establish this pattern, it is proposed that the azimuth circle of fire be divided into a convenient number of sectors and, in each sector, the minimum effective elevation of the gun be determined.

Essentially the invention comprises a mechanical representation of this dead area pattern that is oriented with respect to the gun and is turned in azimuth therewith, a firing circuit switch that cooperates with the pattern and is moved in elevation in accordance with the movement of the gun, and a pattern setting device that is employed to establish the dead area pattern corresponding to the friendly area surrounding the gun site.

The principal object of the invention is to improve fire cutoff or dead area control devices for ordnance equipment. Further objects of the invention are to render gunfire cutoff devices more exible in operation, more quickly adaptable to a given location, and more readily adjustable to conform to changing tactical conditions.

A preferred form of the invention is shown in the accompanying drawings, in which: y

Fig. 1 is an isometric view of a gunfire cutoff device equipped with the invention;

Fig. 2 is a schematic view of the basic elements of the structure of Fig. l;

Fig. 3 is a wiring diagram of the fire cutoff portion of a firing circuit and the pattern setting circuit; and

Fig. 4 is an `isometric view of a portion of the iire cutoff mechanism.

In the form shown in the drawings, the invention is adapted for use on a gun having a barrel I (see Fig. 2) that is mounted for complete freedom of rotation in azimuth about an axis 2, and may be raised in elevation about an axis 3 substantially to the zenith for anti-aircraft activity and depressed at least one hundred mils below the horizontal for use against ground targets. Such a gun is equipped with suitable azimuth and elevation drive mechanisms, and is provided with a solenoid actuated ring circuit. For the purposes of this description, these devices are considered conventional and are not described since it will be apparent that the system may readily be adapted for any dead area control application without departing from the scope of the invention.

In order to provide a framework for the mechanical representation of the dead area pattern, the invention includes a hollow cylinder Ill (Figs. 1 and 2) that is mounted for rotation in suitable bearings (not shown) that are fixed to the gun mount. This cylinder is rotated from the azimuth drive of the gun through a flexible shaft 4 and a drive connection II having a gear I2 xed thereon that meshes Vwith a ring gear I3 fixed on the cylinder. A suitable gear ratio is provided so that the cylinder makes one complete revolution for each complete revolution or 6400 mil travel in azimuth of the gun. In the present arrangement cylinder Ii) is provided with sixtyfour parallel slots I4 equally spaced about its periphery at 100 mil intervals. Each slot serves as a guideway for an associated slide member I5 (see also Fig. 4) which is curved to t the inner surface of the cylinder and is provided with an extension I6 that projects through the slot and terminates in a rack portion I'I. Each slide member I5 extends transversely of its slot through an arc that subtends an angle of approximately fty mils on either side, so that adjacent slides serve to form aV substantially continuous surface.

Each slide is provided with a slotted leaf spring IS that bears against the outer surface of the cylinder, and has a midportion formed as a seat for a short pin I9 that extends through a hole in extension I By this arrangement, each slide member I5 is held snugly against the inner face of the cylinder and may be moved longitudinally in its slot, by means described below, whereby a pattern of the dead area surrounding the gun may be formed.

Cooperating with slide members I5 is an actuating element or plunger 20 for a microswitch 2| that is mounted for movement longitudinally of the slide members on a lead screw 22 that is mounted for rotation on a suitable bracket xed to the gun mount. Lead screw 22 is rotated from the elevation drive of the gun through a iexible shaft 5, drive connection 23 and gears 24 and 25, whereby these elements constitute a means to move the switch 2I and actuating element or plunger 20 in accordance with the movement of the gun in elevation. In a typical application, the amount of longitudinal movement that may be imparted to switch 2I is proportional to a movement of the gun from approximately minus 100 mils elevation to substantially its zenith. Plunger 20 of microswitch 2l (see also Fig. 3) is resiliently urged by a spring 27 to its outward position against cylinder I0 in which it is elective to close the firing circuit of the gun. When plunger 20 engages or rides on a slide'I5, it opens 4 the ring circuit and closes a circuit to a warning lamp 4I that serves as a signal to the gun crew that the gun is aimed at a dead area position.

By the foregoing arrangement, when slides I5 are set in a pattern representing the dead area surrounding the gun, rotation of the gun in azimuth causes cylinder I0 to rotate and thereby bring each slide I5 successively in alignment with plunger 20 of switch ZI; whereas, movement of the gun in elevation causes plunger 23 to move longitudinally to slides I5. Thus, in any given position of the gun in azimuth and elevation in which plunger 2@ contacts ay slide I5, the firing circuit is opened and the gun is prevented from firing, whereas, when the plunger is not in contact with a slide the firing circuit is closed and the gun may be red.

In order to position slides I5 in a pattern representing the surrounding dead area, the invention provides a slide setting mechanism that is operated by the gunner as soon as the gun is in position. For this purpose, a lead screw 30, having a pitch corresponding to that of the teeth in racks I'I, is rotatably mounted in a bracket 3I that is pivoted on a frame 32 fixed to the gun mount. Bracket 3I is spring urged (counterclockwise in Fig. 1) to hold lead screw 30 out of engagement with any of the racks I'I. When it is desired to position a slide I5, a setting plunger 33 is depressed which, through bracket 3|, moves lead screw 30 into engagement with a rack I'I.

Also mounted on setting plunger 33 is a collar 34 that cooperates with a switch actuating member 35 that is connected to the armatures of a microswitch assembly 36. Switch assembly 36 comprises two single pole, double throw microswitches 3T and 38 which comprise a starting circuit for a two-phase capacitor motor Ill which, through suitable gearing, is effective to rotate lead screw 30. Depressing setting plunger 33 actuates switches 3l and 38' to divert line voltage from the firing solenoid circuit to one side of motor 40.

If, because of the position of the gun at the time of setting, plunger 20 is actuated by a slide I5, line voltage is diverted from the firing solenoid circuit to the other side of the motor capacitor. Since line voltage is directly connected between the windings, the induction motor will rotate in the direction which moves the slide away from plunger 20, opening microswitch 2|. As soon as the microswitch opens, the motor reverses, and the slide is moved towards plunger 20, As long as setting plunger 33 is held in, the motor alternately reverses direction under control of actuating element or plunger 20, thereby causing the slide to oscillate relative to the plunger. The continual reversing of the motor, which alternately opens and closes microswitch 2| through the oscillating slide, causes lamp 4I to ash on and off, indicating to the operator that the slide is in proper adjustment. A suitable friction brake 42 is employed to limit the amplitude of oscillation of the slides I5 while they are being positioned.

In practice, as soon as a gun equipped with the invention is unlimbered and levelled in a given position, the dead areas within range of the gun are determined in terms of gun azimuth and elevation. The gun is then manually set to the nearest mil graduation, as read on the azimuth dial, whereby cylinder I0 is rotated through the azimuth drive to bring the rack I'I on the Selected slide I5 in register with lead screw 3B. If no nre cutoff is required in that sector, the gun is then depressed in elevation to its lower limit'. If fire cutoi is required, the gun is elevated to, or slightly above, the elevation angle beneath which gunfire is not wanted.

In either case, switch is positioned accordingly, with reference to the selected slide I5, by the elevation drive. Plunger 33 is then depressed to engage lead screw Sil with the associated rack Vi and to energize motor l0 to drive slide I5 in the required direction. The plunger is held depressed until lamp 4l flashes, indicating that the fire cutoi control for that sector is properly positioned. This procedure is then repeated for each of the remainingr azimuth sectors, in sequence, to complete the firing cutoff control for that gun location.

It may be noted that the use of 100 mil azimuth sectors, in the present instance, is purely a matter of choice since it is apparent that the invention may readily be adapted for use with any size sector. The ultimate choice is primarily a matter of tactical consideration that is determined as a function of the relative importance of `accuracy of control and the time required to set the control.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. In combination with a circuit making and breaking switch, a switch actuating element movable to one position to open the switch and to another position to close the switch, resilient means to urge the actuating element to one of said positions, a plurality of individually settable members to engage the actuating element, said members being eiective when engaged with the actuating element to move it to its other position, means to move the plurality of members transversely to the actuating element, means to move the actuating element longitudinally to the plurality of members, and means to vary the setting of each member of the plurality of members.

2. In combination with a circuit making and breaking switch, a switch actuating element movable to one position to open the switch and to another position to close the switch, resilient means to urge the actuating element to one of said positions, a plurality of individually settable members to engage the actuating element, said members being effective when engaged with the actuating element to move it to its other position, means to cause movement of the actuating element relative to the plurality of members, means to cause movement of the plurality of members relative to the actuating element, means to vary the setting of each member of the plurality of members, and means controlled by the actuating element to determine the direction and extent of operation of the last recited means.

3. In combination with a circuit making and breaking switch, a switch actuating element movable to one position to open the switch and to another position to close the switch, resilient means to urge the actuating element to one of said positions, a plurality of individually settable members to engage the actuating element, said members being effective when engaged with the actuating element to move it to its other position, means to cause movement of the actuating element relative to the plurality of members,

means to cause movement of the plurality of members relative to the actuating element, driving means to vary the setting of the plurality of members, means selectively to engage the driving means with each member of the plurality of members, and means controlled by the actuating element to determine the direction and extent of operation of the driving means.

4. A dead area control system for a gun comprising a switch to open and close the firing circuit of the gun, a switch actuating element movable to one position to open the switch and to another position to close the switch, resilient means to urge the actuating element to one of said positions, a plurality of individually settable members arranged for movement to engage the actuating element, said members being eiective when thus engaged to move the actuating element to its other position, means to move the plurality of members relative to the actuating element proportionally to the azimuth movement of the gun, means to move the actuating element relative to the plurality of members proportionally to the elevation movement of the gun, means to vary the setting of each member of the plurality of members, and means controlled by the actuating element to determine the direction and extent of operation of the last recited means.

5. A dead area control system for a gun comprising a switch to open and close the ring circuit of the gun, a switch actuating element movable to one position to open the switch and to another position to close the switch, resilient means to urge the actuating element to one of said positions, a plurality of individually settable members arranged for movement to engage the actuating element, said members being eiective when thus engaged to move the actuating element to its other position, means to move the plurality of members relative to the actuating element proportionally to the azimuth movement of the gun, means to move the actuating element relative to the plurality of members proportionally to the elevation movement of the gun, driving means to vary the setting of the plurality of members, means selectively to engage the driving means with each member of the plurality of members, and means controlled by the actuating element to determine the direction and extent of operation of the driving means.

6. A dead area control system for a gun comprising a switch to open and close the ring circuit of the gun, a switch actuating element movable to one position to open the switch and to another position to close the switch, resilient means to urge the actuating element to one of said positions, a plurality of individually settable members arranged for movement to engage the actuating element, said members being effective when thus engaged to move the actuating element to its other position, means to move the plurality of members transversely to the actuating element proportionally to the azimuth movement of the gun, means to move the actuating element longitudinally to the plurality of members proportionally to the elevation movement of the gun, means to vary the setting of each member of the plurality of members, and means controlled by the actuating element to determine the direction and extent of operation of the last recited means.

7. A dead area control system for a gun comprising a switch to open and close the firing circuit of the gun, a switch actuating element movable to one position to open the switch and to another position to close the switch, resilient means to urge theV actuating element. to one of said positions, a plurality of individually settable members arranged for movementl to engage the actuating element, said members being effective when thus engaged to move the actuating element to its other position, meansto move the plurality of members transversely to the actuating element proportionally to the azimuth movement of the gun, means to move the actuating element longitudinally to the plurality of members proportionally to the elevation movement of the gun, driving means to vary the setting of the plurality of members, means selectively to engage the driving means with each member of the plurality of members, and means controlled by the actuating element to determine the direction and extent of operation of the driving means.

.8. A dead area control system for a gun comprising a switch to open and close the ring circuit of the gun, a switch actuating element movable to one position to open the switch and to another position to close the switch, resilient means to urge the actuating element to one of said positions, a plurality of individually settable members arranged for movement to engage the actuating element, said members being eiective when thus engaged to move the actuating element to its other position, means to move the plurality of members transversely to the actuating element proportionally to the azimuth movement of the gun, means to move the actuating element longitudinally to the plurality of members proportionally to the elevation movement of the gun, means to vary the setting of each member of the plurality of members, means controlled by the actuating element to determine the direction and extent of operation of the last recited means, and signalling means operable upon the engagement of the actuating element with any of the plurality of members.

9. A dead area control system for a gun comprising a switch to open and close the ring circuit of the gun, a switch actuating element movable to one position to open the switch and to another position to close the switch, resilient means to urge the actuating element to one of said positions, a plurality of individually settable members arranged for movement to engage the actuating element, said members being effective when thus engaged to move the actuating element to its other position, means to move the plurality of members transversely to the actuating element proportionally to the azimuth movement of the gun, means to move the actuating element longitudinally to the plurality of members proportionally to the elevation movement of the gun, driving means to vary the setting of the plurality of members, means selectively to engage the driving means with each member of the plurality of mem-bers, means controlled by the actuating element to determine the direction and extent of operation of the driving means, and signalling means operable upon the engagement of the actuating element with any of the plurality of members.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,045,251 Raber June 23, 1936 2,163,190 Carlson et al June 20, 1939 2,194,311 Leonard Mar. 19, 1940 2,415,967 Pontius Feb. 18, 1947 2,483,385 Humphrey Sept. 27, 1949 2,542,483 Fonseca Feb. 20, 1951 

